Development of the PsAQoL: a quality of life instrument specific to psoriatic arthritis

Abstract

Background: Patient reported outcome measures used in studies of psoriatic arthritis (PsA) have been found to be inadequate for determining the impact of the disease from the patient's perspective. Objective: To produce the PsAQoL, a PsA-specific quality of life (QoL) instrument, employing the needs based model of QoL that would be relevant and acceptable to respondents, valid, and reliable. Methods: Content was derived from qualitative interviews conducted with patients with PsA. Face and content validity were assessed by field test interviews with a new sample of patients with PsA. A postal survey was conducted to improve the scaling properties of the new measure. Finally, a test-retest postal survey was used to identify the final measure and to test its scaling properties, reliability, internal consistency, and validity. Results: Analysis of the qualitative interview transcripts identified a 51 item questionnaire. Field test interviews confirmed the acceptability and relevance of the measure. Analysis of data from the first postal survey (n = 94) reduced the questionnaire to 35 items. Rasch analysis of data from the test-retest survey (n = 286) identified a 20 item version of the PsAQoL with good item fit. This version had excellent internal consistency (a = 0.91), test-retest reliability (0.89), and validity. Conclusions: The PsAQoL is a valuable tool for assessing the impact of interventions for PsA in clinical studies and trials. It is well accepted by patients, taking about three minutes to complete, is easy to administer, and has excellent scaling and psychometric properties.

Reliability and Validity of the Turkish Adaptation of VITACORA-19 in Patients with Psoriatic Arthritis

“…Pain may interfere with the activities related to daily life and thus cause poor functional status and diminished QoL. Similar to our study, McKenna et al 13 and Billing et al 19 reported a significant correlation between subgroups of NHP and PsQoL scores. Thus, we can consider the Turkish version of VITACORA-19 as a questionnaire that evaluates the QoL of PsA patients multi-dimensionally.…”

“…As in our study, they also showed no effect of the presence of psoriasis treatment on PsQoL. 13 In the study by Wink et al, 18 the male patients had higher PsQoL scores, as in our study. Similar to the previous studies, patients who do not perceived current severity of arthritis as mild or those who had no flare of arthritis had higher VITACORA-19 score indicating that presence and severity of arthritis are among the main parameters determining the level of HRQoL.…”

“…In the original study by Torre-Alonso et al, the effects of demographic data (sex, marital, employment and educational statuses) on VITACORA-19 had not been assessed. 20 McKenna et al 13 demonstrated no influence of sex or marital status on PsQoL. As in our study, they also showed no effect of the presence of psoriasis treatment on PsQoL.…”

“…[10][11][12] Self administered Psoriatic Quality of Life (PsQoL) scale was developed to evaluate the QoL of patients with PsA. 13 A validity study for the Turkish version of PsQoL was performed by Duruöz et al, 14 who demonstrated PsQoL to be relevant and acceptable to respondents, valid, and reliable with proven sensitivity to changes. 15,16 HRQoL is an important outcome for daily practice and evidence based data; however, to our knowledge, limited number of publications are present regarding PsQoL questionnaires in PsA.…”

Disease burden of psoriatic arthritis compared to rheumatoid arthritis, Hungarian experiment

“…Patients filled in the validated Hungarian version of the Health Assessment Questionnaire (HAQ), EQ-5D and Psoriatic Arthritis Quality of Life Questionnaire (PsAQoL) [5][6][7][8].…”